Measurements Of The Radar Cross Section And Inverse Synthetic Aperture Radar Isar Images Of A Piper Navajo At 9 5 Ghz And 49 Ghz
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Measurements Of The Radar Cross Section And Inverse Synthetic Aperture Radar Isar Images Of A Piper Navajo At 9 5 Ghz And 49 Ghz
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Author :
language : en
Publisher:
Release Date : 1993
Measurements Of The Radar Cross Section And Inverse Synthetic Aperture Radar Isar Images Of A Piper Navajo At 9 5 Ghz And 49 Ghz written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with categories.
Studies were conducted of the enhanced radar cross section (RCS) and improved inverse synthetic aperture radar (ISAR) image quality that may result at millimeter-wave (mmw) frequencies. To study the potential for mmw radar in these areas, a program was initiated in FY 90 to design and fabricate a 49.0- to 49.5-GHz stepped-frequency radar. After conducting simultaneous measurements of the RCS of an airborne Piper Navajo twin-engine aircraft at 9.0 and 49.0 GHz, the RCS at 49.0 GHz was always found to be higher than at 9.0 GHz by an amount that depended on the target aspect angle. The largest increase was 19 dB and was measured at nose-on incidence; at other angles of incidence, the increase ranged from 3 to 10 dB. The increase averaged over a 360-degree aspect-angle change was 7.2 dB. The 49.0-GHz radar has demonstrated a capability to gather well- calibrated millimeter-wave RCS data of flying targets. In addition, the successful ISAR images obtainable with short aperture time suggest that 49.0-GHz radar may have a role to play in noncooperative target identification (NCTI) ... Millimeter-wave(mmw) radar frequencies, Radar Cross Section(RCS) data, Inverse Synthetic Aperture Radar(ISAR) images.
Government Reports Annual Index
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Author :
language : en
Publisher:
Release Date : 1993
Government Reports Annual Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Government reports announcements & index categories.
Government Reports Announcements Index
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Author :
language : en
Publisher:
Release Date : 1993-11
Government Reports Announcements Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993-11 with Science categories.
Theoretical And Experimental Study Of Radar Cross Section And Microwave Imaging Microform
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Author : Beibei Zhang
language : en
Publisher: National Library of Canada = Bibliothèque nationale du Canada
Release Date : 1998
Theoretical And Experimental Study Of Radar Cross Section And Microwave Imaging Microform written by Beibei Zhang and has been published by National Library of Canada = Bibliothèque nationale du Canada this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Microwave imaging categories.
This thesis addresses a number of topics associated with microwave scattering from conducting objects such as Radar Cross Section (RCS) measurements, Inverse Synthetic Aperture Radar (ISAR) image reconstruction and their applications to radar target identification. An overview of experimental techniques for RCS determination and theoretical analysis of several standard scatterers used in RCS measurements is presented. An efficient deconvolution technique based on Singular Value Decomposition (SVD) is implemented to be used in measured data analysis. A number of experimental results are obtained from the facilities available in the UWO Electromagnetic Wave Laboratory and compared to the theoretical results. Different ISAR image reconstruction algorithms are formulated, implemented and tested on both simulated and measured data. A new target identification technique based on joint Physical Optics (PO) and Finite Difference Time Domain (FDTD) representations of the scattered response is introduced. The application of wavelets in ISAR is a new research direction and another contribution of this thesis is the best wavelet evaluation for data compression and denoising in target identification.
Utilizing Near Field Measurements To Characterize Far Field Radar Signatures
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Author : John R. Watkins
language : en
Publisher:
Release Date : 2004-06-01
Utilizing Near Field Measurements To Characterize Far Field Radar Signatures written by John R. Watkins and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004-06-01 with Image processing categories.
The increased need for stealth aircraft requires an on-site Far-Field (FF) Radar Cross-Section (RCS) measurement process. Conducting these measurements in on-site Near-Field (NF) monostatic facilities results in significant savings for manufacturers and acquisition programs. However, NF measurements are not directly extended to a FF RCS. Therefore, a large target Near-Field to Far-Field Transformation (NFFFT) is needed for RCS measurements. One approach requires an Inverse Synthetic Aperture Radar (ISAR) process to create accurate scattering maps. The focus of this work is the development of accurate NF scattering maps generated by a monostatic ISAR process. As a first look, the process is isolated to a simulated environment to avoid the uncontrollable effects of real measurement environments. The simulation begins with a NF Synthetic Target Generator (STG) which approximates a target using scattering centers illuminated by spherical electromagnetic waves to approximating NF scattering. The resulting NF In-phase and Quadrature (IQ) data is used in a "Trapezoidal" ISAR process to create spatially distorted images that are accurately corrected within the ISAR process resolution using a newly developed NF correction. The resulting spatially accurate ISAR images do not complete the NFFFT. However, accurate scattering maps are essential for process development.
Effect Of Phase Errors In Stepped Frequency Radar Systems
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Author : H. E. VanBrundt
language : en
Publisher:
Release Date : 1988
Effect Of Phase Errors In Stepped Frequency Radar Systems written by H. E. VanBrundt and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with categories.
Stepped-frequency waveforms are being considered for inverse synthetic aperture radar (ISAR) imaging from ship and airborne platforms and for detailed radar cross section (RCS) measurements of ships and aircraft. These waveforms make it possible to achieve resolutions of 1.0 foot by using existing radar designs and processing technology. One problem not yet fully resolved in using stepped-frequency waveform for ISAR imaging is the deterioration in signal level caused by random frequency error. Random frequency error of the stepped-frequency source results in reduced peak responses and increased null responses. The resulting reduced signal-to-noise ratio is range dependent. Two of the major concerns addressed in this report are radar range limitations for ISAR and the error in calibration for RCS measurements caused by differences in range between a passive reflector used for an RCS reference and the target to be measured. In addressing these concerns, NOSC developed an analysis to assess the tolerable frequency error in terms of resulting power loss in signal power and signal-to-phase noise.
In Situ High Resolution Radar Imaging Of Dynamic Targets Using An Ultra Wideband Radar
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Author : Chenchen Jimmy Li
language : en
Publisher:
Release Date : 2016
In Situ High Resolution Radar Imaging Of Dynamic Targets Using An Ultra Wideband Radar written by Chenchen Jimmy Li and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
This dissertation investigates in-situ, high-resolution radar imaging of dynamic targets using an ultra-wideband (UWB) radar. Three challenging classes of dynamic targets are investigated: wind turbines, vehicles, and small consumer drones. First, the measurement and processing methodologies are developed to capture the inverse synthetic aperture radar (ISAR) image of an operating horizontal-axis wind turbine. Measurement data of a small three-blade wind turbine are collected using a UWB radar, and the measured signatures are compared to simulation results based on physical optics. The backscattering phenomenology is examined in the sinogram, spectrogram, and ISAR image domains. The same methodologies are then applied to generate the in-situ ISAR imagery of an 18-blade windmill and a 1.7 MW utility-class wind turbine. Next, the radar signatures of a vertical-axis wind turbine are studied. Measurement and simulation are carried out for a 1.5 m tall Darrieus-type turbine model. Interpretation of the dominant backscattering mechanisms is carried out. Subsequently, the radar signatures of a 112 m tall turbine are examined using simulation. Second, wide-angle ISAR imaging of vehicles is investigated. Measurement data of moving vehicles are collected using a stationary roadside UWB radar. The generated baseline ISAR images show a clear distinction between different-sized vehicles. The images are further focused through motion compensation using a p-norm minimization. The resulting images are well focused and correspond closely to the physical dimensions of the vehicles. Third, the ISAR imaging of small consumer drones is considered. Laboratory measurement is conducted first, where the drones are rotated on a turntable and the backscatterered data are collected over a wide frequency band to form high-resolution images. The effects of frequency band, aspect, polarization, dynamic blade rotation, camera mount, and drone types are examined. Subsequently, ISAR imaging of in-flight drones, from data collected using a stationary UWB radar on the ground, is demonstrated. Finally, synthetic aperture radar (SAR) imaging using a small drone as the radar platform is explored. The entire system including a UWB radar, antennas, a camera, and a single-board computer fits on the small drone and is controlled through a Wi-Fi connection. Both the side-looking and downward-looking SAR scenarios are presented.
Isarlab
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Author : Defence Science and Technology Organisation (Australia)
language : en
Publisher:
Release Date : 1999
Isarlab written by Defence Science and Technology Organisation (Australia) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Imaging systems categories.
ISARLAB ("Inverse Synthetic Aperture Radar Laboratory") is a computer program designed as a research and training tool for those interested in the field of radar imaging. The system runs under MATLAB and is capable of simulating the radar returns from complex targets such as ships and aircraft, and processing these to form high range resolution (HRR) profiles and inverse synthetic aperture radar (ISAR) images. In addition to simulating various radars and targets in realistic scenarios, ISARLAB can accept and process experimentally collected radar data. This document represents the combination of a reference guide and a user's guide to the software package, as well as providing a brief introduction to radar imaging.
Passive Radar Imaging With Multiple Transmitters
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Author : Aaron Brandewie
language : en
Publisher:
Release Date : 2021
Passive Radar Imaging With Multiple Transmitters written by Aaron Brandewie and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Compressed sensing (Telecommunication) categories.
Passive radar systems use signals of opportunity to illuminate targets instead of dedicated radar transmitters. The signals of opportunity have lower bandwidth than dedicated active radar systems, leading to poor downrange resolution. Multiple signals of opportunity can be coherently combined to increase the overall bandwidth of the system, and therefore create finer resolution images. These signals are usually separated in the frequency domain (non-contiguous), which causes large unwanted grating lobe artifacts in the image when using back-projection or Fourier transform based imaging. Additionally, the signals of opportunity may be completely uncorrelated and transmitting from different locations. This dissertation investigates methods of combining these signals to create images with higher resolution than if only a single signal of opportunity were used. A method to quickly estimate bistatic scattered electric fields from complex targets is augmented with new models. The targets are first decomposed into a set of canonical geometries with closed-form solutions. Then the total scattered field of the target is found as the superposition of the scattered fields from the individual geometries. The canonical geometries used are plates, dihedrals, and trihedrals. A closed-form solution for the non-90° dihedral is introduced and verified with iterative physical optics. Bistatic SAR images of complex targets can be predicted in seconds using the total scattered fields from the canonical geometries, whereas it would take hours using a physical optics solver. Approaches of combining signals for 1D passive radar imaging are then examined. The signals may be non-contiguous in frequency, and originate from transmitters not located at the same position. A calibration method is developed to align the downrange responses, and coherently combine the two signals. A compressive sensing-based algorithm is used to combine the non-contiguous frequency data, and is shown to mitigate the grating lobe artifacts that occur when using a back-projection algorithm. This approach is verified using simulated data, and experimental data of commercial aircraft collected with the ElectroScience Lab (ESL) digital television passive (DTV) passive radar system. It is shown that the compressive sensing-based algorithm can provide finer resolution images, without the presence of grating lobes when the frequency is non-contiguous. The imaging approach developed for 1D downrange profiles is then extended for 2D Inverse Synthetic Aperture Radar (ISAR) imaging. A measurement duration is multiple seconds for ISAR imaging, due to the need of collecting scattered signals from multiple aspect angles for increased cross-range resolution. A motion compensation algorithm is developed to estimate the uncooperative target’s kinematics, and to keep the imaging plane focused on the target as it moves. This algorithm is demonstrated using both simulated, and experimental data of commercial aircraft collected with the ESL DTV passive radar system. Additionally, it is demonstrated that the compressive sensing-based algorithm is able to improve the resolution of the image and resolve point scatterers that cannot be observed in a back-projection image.
Radar Cross Section Measurement Of A 50 Caliber Bullet At Ka Band
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Author :
language : en
Publisher:
Release Date : 2007
Radar Cross Section Measurement Of A 50 Caliber Bullet At Ka Band written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
Static radar cross-section (RCS) measurements of a pristine .50 caliber bullet at Ka-band are reported. Measurements are from 32.4-GHz to 35.6-GHz using a stepped frequency waveform with range resolution of 4.7-cm. The measurements are compared with model data and have good agreement. The data was collected during the summer of 2003 at the Army Research Laboratory's (ARL) millimeter wave anechoic chamber research facility located at the Adelphi Laboratory Center (ALC), Maryland.